It is known that in order to ensure long duration conservation of foodstuffs without subjecting them to particular refrigeration conditions, it is necessary for the foodstuff to be conditioned aseptically, i.e. without germs being introduced into the receptacle during the various stages of packaging. In order to ensure that packaging is aseptic, it is known in particular that it is necessary to subject the line of machines used for packaging to sterile conditions that are generally obtained by implementing a laminar flow of filtered air that flows vertically over the line of machines.
For this purpose, existing aseptic packaging installations, such as that described in particular in document FR-A-2 800 710, comprise a cabin that provides a highly aseptic packaging zone around the line of machines, at least one side of the packaging zone being adjacent to an operator zone that is maintained under conditions that are less aseptic than the conditioning zone by providing for air to flow from the packaging zone towards the operator zone through openings in a partition common to the packaging zone and the operator zone. Similarly, document EP 1 251 085 describes enclosures forming a packaging zone at a pressure higher than atmospheric pressure, surrounded by an enclosure at atmospheric pressure forming an operator zone.
It has been found that when a technician seeks to act on the line of machines, either for periodic maintenance, or because of a problem that has arisen during the operation of one of the machines, opening a door providing communication between the operator zone and the packaging zone leads to turbulence that runs the risk of causing less-aseptic air to penetrate from the operator zone into the packaging zone, thereby causing the air in the packaging zone to become less aseptic.
It is also known from document DE 103 40 876 to cause air to flow vertically by disposing a first enclosure at a pressure P1 higher than a pressure P2 that exists in a second enclosure to be disposed one above the other, where P2 is higher than atmospheric pressure. Such an installation does not provide for the possibility of lateral access.